﻿//-----------------------------------------------------------------------
// <copyright file="Future.cs" company="Nathan Miller">
// Copyright (c) Nathan Miller.
//
// Permission is hereby granted, free of charge, to any person obtaining
// a copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to
// permit persons to whom the Software is furnished to do so, subject to
// the following conditions:
// 
// The above copyright notice and this permission notice shall be
// included in all copies or substantial portions of the Software.
// 
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
// LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
// OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
// </copyright>
//-----------------------------------------------------------------------
namespace TileTool.Base.Threading.Future.Generic
{
    using System;
    using System.ComponentModel;
    using TileTool.Threading.Future;
    using TileTool.Threading.Future.Generic;

    /// <summary>
    /// Implementation of the generic future interface.
    /// </summary>
    /// <typeparam name="ResultType">Type of result provided by the future object.</typeparam>
    public class Future<ResultType> : Future, IFuture<ResultType>
    {
        #region Fields - Private

        /// <summary>
        /// Result value.
        /// </summary>
        private ResultType result;

        #endregion

        #region Constructor

        /// <summary>
        /// Default constructor.
        /// </summary>
        public Future()
        {
            this.result = default(ResultType);
        }

        #endregion

        #region Properties - Public

        /// <summary>
        /// Gets the result of the future object. Only valid when 
        /// Complete is true and IsError is false.
        /// </summary>
        public ResultType Result
        {
            get
            {
                lock (this.LockObject)
                {
                    if (this.State != FutureState.Completed)
                    {
                        throw new InvalidOperationException("You cannot get the result of the operation until is is complete.");
                    }

                    return this.result;
                }
            }

            set
            {
                lock (this.LockObject)
                {
                    this.result = value;
                }
            }
        }

        #endregion

        #region Methods - Public

        /// <summary>
        /// Implementation of the OnComplete() interface function.
        /// </summary>
        /// <param name="func">Method to call.</param>
        public void OnComplete(Action<IFuture<ResultType>> func)
        {
            lock (this.LockObject)
            {
                if (this.State == FutureState.Completed)
                {
                    func(this);
                    return;
                }

                this.AddCompleteAction(() => func(this));
            }
        }

        #endregion
    }
}
